1. Field of the Invention
The present invention relates to a network management system and more particularly to the network management system being suitable for acquiring information about a path through which a packet has passed in a network which is of a connectionless mode communication type.
2. Description of the Related Art
In a general network management system, for example, a device adapted to manage the network acquires information about connection among transmission paths housed in units making up nodes on the network and about packets having passed through the transmission paths and, based on the acquired information, produces information about a path of a network through which a packet has passed, that is, information indicating contents of the packet having passed through the path and kinds or numbers of the paths through which the packet has passed and holds the information. Such conventional technology is disclosed in Japanese Patent Application Laid-open Nos. Hei 10-224350 and 2000-216830.
However, in the conventional connectionless-type network management system, when the network managing device acquires information about a series of paths existing between a unit which has originally produced a packet and a destination of the packet transmission, processing of having information about the passage of each of packets supplied from all nodes to the network managing device in each of nodes is required, irrespective of whether or not the packet has passed in each of nodes. That is, irrespective of whether or not a packet passes through a node, setting to cause the node to provide information about the passage of the packet is needed, which is wasteful processing. Moreover, the network managing device acquires information about the node through which the packet does not pass, which is also wasteful processing.
In some cases, the network management unit requires that not only the information about the path but also information about delay time in the passage of packets in each of the nodes as information to be used for management be provided. If such the processing is required, when the packet does not pass through the node, it means that further additional wasteful processing is performed.
Furthermore, as the number of nodes to be installed on the network increases, the number of the nodes from which information has to be acquired increases and, as a result, processing that has to be performed by the network managing system becomes complicated.
Same problems as described above occur not only in the connectionless network but also a connection oriented type network in which communications are carried out with the connection being established in advance. That is, it means that the network managing device has to acquire information from all the nodes whose connection has been established.